widget/gtk/WidgetTraceEvent.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "mozilla/WidgetTraceEvent.h"
   6
   7 #include <glib.h>
   8 #include <mozilla/CondVar.h>
   9 #include <mozilla/Mutex.h>
  10 #include <stdio.h>
  11
  12 using mozilla::CondVar;
  13 using mozilla::Mutex;
  14 using mozilla::MutexAutoLock;
  15
  16 namespace {
  17
  18 Mutex* sMutex = nullptr;
  19 CondVar* sCondVar = nullptr;
  20 bool sTracerProcessed = false;
  21
  22 // This function is called from the main (UI) thread.
  23 gboolean TracerCallback(gpointer data) {
  24   mozilla::SignalTracerThread();
  25   return FALSE;
  26 }
  27
  28 }  // namespace
  29
  30 namespace mozilla {
  31
  32 bool InitWidgetTracing() {
  33   sMutex = new Mutex("Event tracer thread mutex");
  34   sCondVar = new CondVar(*sMutex, "Event tracer thread condvar");
  35   return true;
  36 }
  37
  38 void CleanUpWidgetTracing() {
  39   delete sMutex;
  40   delete sCondVar;
  41   sMutex = nullptr;
  42   sCondVar = nullptr;
  43 }
  44
  45 // This function is called from the background tracer thread.
  46 bool FireAndWaitForTracerEvent() {
  47   MOZ_ASSERT(sMutex && sCondVar, "Tracing not initialized!");
  48
  49   // Send a default-priority idle event through the
  50   // event loop, and wait for it to finish.
  51   MutexAutoLock lock(*sMutex);
  52   MOZ_ASSERT(!sTracerProcessed, "Tracer synchronization state is wrong");
  53   g_idle_add_full(G_PRIORITY_DEFAULT, TracerCallback, nullptr, nullptr);
  54   while (!sTracerProcessed) sCondVar->Wait();
  55   sTracerProcessed = false;
  56   return true;
  57 }
  58
  59 void SignalTracerThread() {
  60   if (!sMutex || !sCondVar) return;
  61   MutexAutoLock lock(*sMutex);
  62   if (!sTracerProcessed) {
  63     sTracerProcessed = true;
  64     sCondVar->Notify();
  65   }
  66 }
  67
  68 }  // namespace mozilla